Patterns of racial and ethnic marital endogamy among recent immigrants (1) indicate the extent of immigrant adaptation and acculturation, (2) influence the strength of conventional racial and ethnic boundaries, and (3) affect the future racial and ethnic composition of the U.S.population. The detailed racial and ethnic information available from the 2000 U.S. Census, alone and in combination with data from earlier decennial Censuses, provides an unprecedented opportunity to address the research objective and to cast new light on the marital assimilation of new immigrant groups. This project has three specific goals. First, it documents temporal changes and racial and ethnic variation in union formation among immigrants and natives. This study uses a two-sex approach to compare nativity differences in marriage and cohabitation by men and women's joint characteristics. Second, the proposed study, utilizes log-rate models to evaluate immigrants' changing patterns of assortative mating, while controlling for the availability of eligible partners by race and ethnicity, nativity, and educational attainment, as well as the changing composition of the population across these characteristics. The 2000 Census provides detailed racial and ethnic information to examine racial and ethnic variation in immigrants' marriage patterns - the extent of marriage with immigrants of the same racial and ethnic group, with natives of the same racial and ethnic group, with persons within pan-ethnic or racial group, with persons of a different pan-ethnic or racial minority group, and with non-Hispanic whites. Third, this project examines differences in assortative mating patterns for different racial and ethnic minority immigrant groups in selected immigrant destinations, Hierarchical generalized linear models measure the impact of various local marriage market conditions (i.e., racial diversity) on assortative mating patterns and identify within- and between-area variations in the likelihood of interracial marriage or interethnic marriage among natives and immigrants.